this thread from 2010 lol i think some changes have made since 2010...
B. A template is adjusted for uCoz.
1. First of all download the template.
2. Then view what you have downloaded – if it is a general template then you can apply it for all pages except the forum (unless the template description says that is can be used for forum as well).
3. Go to your website CP (http://your_site.ucoz.com/admin): Main » Customize Design » Template Builder.
4. Make sure that the downloaded archive has: tmpl.txt (main template code), styles.css (CSS styles), and the folder 'img' (where all template images are stored).
5. Open tmpl.txt (e.g. by means of the notepad), copy the whole text (ctr+A, ctr+C), and paste it into Template Builder.
6. Then go to Customize Design » Style sheets (CSS). Open styles.css (e.g. by means of the notepad), copy the whole text (ctr+A, ctr+C), and paste it into the opened CP window.
7. Upload all images from the 'img' folder into File Manager or via FTP.
8. That's all, enjoy you new website design.
P.S. If you have downloaded a template that has a 'css' folder with two files, then you should upload this folder to your File Manager as well.
I cant find that one "Main » Customize Design » Template Builder."